An earlier expression can evoke an associated referent implicitly (كناية) even if the relevant noun has not been spoken outright. A later noun with al- then refers back to the contextually recoverable referent. This requires attention to what the previous words convey, not only their surface vocabulary.
وَلَيْسَ الذَّكَرُ كَالْأُنْثَى
And the male is not like the female.
In this passage of Sūrat Āl ʿImrān, the definite forms «الذَّكَر» and «الْأُنْثَى» are interpreted in relation to the preceding and surrounding account of an expected child and the girl who was born. Merely recognizing the grammatical genders misses the contextual comparison. Rhetorical analysis examines reference, contextual implication, and the intended point of contrast.